Brass vs. dieletric waterway fitting dielectric isolators

ALH_4

Brass is not dielectric.

I have never seen a problem with copper threaded directly to cast iron. I have seen rust problems in iron from oxygen diffusion through plastic or rubber tubing. In my opinion, it is a non-issue in residential hydronic heating systems unless there is aluminum in the system.

Darrell Lackey

Brass vs. dieletric waterway fitting dielectric isolators

How can brass valves or nipples work as dielectric isolators when brass, bronze, and copper are very similar on metallurgical charts for causing corrosion when connected to steel or cast iron. They are often pitched as being as good as dielectric waterways (which are better than dielectric unions).